1. Field of the Invention
The present invention relates to an organopolysiloxane and a cosmetic containing it.
2. Description of the Related Art
A silicone oil is used as an oil material in many applications because of its safety and so on. It is widely used in a cosmetic as well; especially a low-viscosity silicone oil having viscosity of 100 mm2/second or less is widely used in applications such as, for example, skin care and make-up cosmetic and the like, because of its excellent spreading properties, refreshing feeling, and safety.
In the field of a cosmetic and the like, a silicone oil is generally used as emulsion; in that case, a silicone surfactant is used in many cases. As the silicone surfactant like this, such as for example, a polyether-modified silicone having a polyoxyalkylene group in the siloxane's terminal or side chain has been known (Japanese Examined Patent Publication No. H04-15762, Japanese Examined Patent Publication No. H04-20407, Japanese Examined Patent Publication No. H05-13126, Japanese Examined Patent Publication No. H06-62385, and Japanese Examined Patent Publication No. H05-12979). In addition, a polyether-modified silicone whose main chain siloxane moiety is branched (Japanese Patent No. 3724988) and a polyether-modified silicone of an ABA-type copolymer (silicone-hydrophilic group-silicone), as shown in the following formula, have been known (Japanese Patent Laid-Open Publication No. 2005-154736),
wherein X represents an arbitrary bonding group, such as a urethane group, a urea group, an amide group, an ester group, and an alkyl ether group. R represents a linear or a branched alkylene group having 1 to 12 carbon atoms, or a phenyl group, wherein “l” represents 1 to 5, “m” represents 40 to 90, and “n” represents 10 to 40.
As to the silicone surfactant, a silicone having, as other hydrophilic groups, a (poly)glycerin group (Japanese Examined Patent Publication No. S62-34039), a silicone having a branched siloxane moiety (Japanese Patent No. 3976226), and a (poly)glycerin-modified silicone as an ABA-type copolymer shown in the following formula (Japanese Patent Laid-Open Publication No. 2006-218472) have also been known. These silicones have been known also as a powder-dispersion stabilizer of a powder-containing cosmetic,
wherein R represents a linear or a branched alkyl group having 1 to 12 carbon atoms or a phenyl group, wherein R′ is exemplified by an alkylene group having 2 to 11 carbon atoms. “m” represents 10 to 120 and “n” represents 1 to 11.